Therapeutic Properties of New Zealand and Australian Tea Trees

There has recently been a significant increase in the use of therapeutically active compounds extracted from plants as opposed to chemically synthesised drugs. The demand for natural products is increasing and in many cases currently exceeds supply. The flora of New Zealand and Australia is rich in unique species, however, very few of these native plants have been tested for medicinal constituents [1]. The family Myrtaceae contains many plants, including the Australian tea tree (Melaleuca alternifolia) and its New Zealand equivalents manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides formerly Leptospermum ericoides), which are currently being investigated for their therapeutic properties. These natives have become known collectively as "tea trees" since Captain Cook used to brew a stong tea from the leaves for his men. They were used extensively by the early settlers of both countries and the Maori and Aboriginal people have been using parts of the tea trees for therapeutic purposes for centuries [2]. Various preparations of the gum, sap, seed pods, leaves, bark and flowers of manuka were used both externally and internally to treat many conditions (Table 1).